3.44pm: Patrick Wintour reports that in a joint statement, Cameron and Sarkozy pledged that their countries "will continue to increase their engagement with the Syrian opposition, including encouraging the opposition to work together and to support the vision of an inclusive, prosperous and free Syria".

Efforts will be made to draw together the opposition at a meeting in Tunis convened by the Friends of Syria Group. The conference is being co-presided by French foreign minister Alain Juppe and his Turkish counterpart Ahmet Davutoglu.

Patrick also gave his view on Cameron's semi-endorsement of Sarkozy in his efforts to be re-elected French president.

It is not normal but not unprecedented for a British prime minister to offer an endorsement of a candidate in an overseas election. Cameron privately believes that the effective campaigning style of Sarkozy will win through.

Cameron said: "[The summit] has given me the chance to wish my friendwell in the battle he has ahead."

Side by side on the podium, David Cameron and Nicolas Sarkozy sought to portray the Franco-British relationship as a strong marriage – they might have differences, might have seen rocky patches but they were staying together. Recent differences over Europe, tension over competition to sell fighter jets to India, Cameron calling Sarkozy's financial transaction tax "mad" or Sarkozy's recent quip that Britain had no industry left seemed to be behind them.

Far from Sarkozy's comments to Cameron in Brussels in October — "You have lost a good opportunity to shut up" and "We are sick of you criticising us and telling us what to do. You say you hate the euro and now you want to interfere in our meetings" — he now seemed to be all compliments for the British prime minister's "courage", even praising his handing of the economic crisis, a subtle message to France on the issue of austerity measures.

But after Sarkozy formally launched his difficult battle for re-election this week, with the earlier backing of Angela Merkel, the key question for Paris observers was whether Cameron would also pledge to back him on the campaign trail.

Cameron said the summit had given him "the chance to wish my friend well in the battle he has ahead". He said he admired Sarkozy's "leadership" and "courage" and said he was "a good thing for his country" but that if he made those comments on Sarkozy's campaign trail he wasn't sure they would "have the effect" Sarkozy might want them to have.

Sarkozy said the more people who said good things about him, "the better".

David Cameron and Nick Clegg with a Great Britain-branded Mini at Gare du Nord station in Paris today. Photograph: Stefan Rousseau/PA

While in Paris, Cameron and Nick Clegg also found time to pose for this memorable photograph with a Mini branded with the words "Great Britain".

Nick Clegg and David Cameron arrive at Gare du Nord station in Paris this morning. Photograph: Stefan Rousseau/PA

2.00pm: David Cameron gave Nicolas Sarkozy a warship shell casing today as a gift to mark the one year anniversary of the Libyan uprising.

The high-explosive remnant is one of just three recovered from the 209 shells fired from HMS Liverpool during its involvement in Libya. Cameron holds one and defence secretary Philip Hammond has the last one.

Its inscription reads: "Presented by the Prime Minister to President Sarkozy on the occasion of the UK-France summit and the first anniversary of the Libyan revolution, 17 February 2012."

HMS Liverpool, based in Portsmouth, Hampshire, was the first navy vessel to be fired on for 30 years while it was off Libya last year.

The Press Association has filed a story on the announcement of British aid to Syria.

The UK is supplying £2m worth of aid, which will provide medical supplies and food for more than 20,000 people affected by the fighting.

The British funding announced today will be channelled through three humanitarian agencies which are active in Syria, but which are not being named in order to avoid the danger of reprisals.

The money will pay for emergency medical services and supplies for those injured in the violence; basic food rations for more than 20,000 people; household items such as cutlery, pots, blankets and towels for up to 5,500 people forced to flee their homes; bottled water for 2,750 people; and the restoration of damaged water and sanitation infrastructure for more than 30,000 people.

An adviser is to be deployed to the region to liaise with agencies already providing humanitarian aid and to promote better co-ordination of international relief efforts.

Andrew Mitchell, the international development secretary, said:

The emerging picture from Syria is increasingly horrifying, and as the shelling of Homs enters its third week our concern for the humanitarian situation continues to grow.

The support that the prime minister has announced today will provide immediate and potentially life-saving short-term help for thousands of innocent civilians under attack - but a longer-term solution is urgently needed.

Humanitarian agencies in the country are doing admirable work, but restraints imposed by the Syrian government mean effectively they have one hand tied behind their back, while many other agencies aren't even able to get access.

The UK government has consistently called for an end to the violence and unimpeded access to Syria for humanitarian agencies. These agencies must be allowed to assess what further help may be required and to meet the urgent needs of all those suffering as a result of the violence.

• David Cameron and Nicolas Sarkozy have held talks in Paris to discuss civil nuclear co-operation between Britain and France and the ongoing unrest in Syria.

• Britain announced it would supply food rations for 20,000 Syrians and the employment of an adviser to liaise with agencies there. Cameron said the situation in Syria was "appalling" and said the government was "butchering and murdering its own people". He said that Syria was different to Libya in three ways: in Libya the west had a UN resolution, the Arab League was calling for action, and the opposition represented the whole country, he said. He called Bashar al-Assad a "brutal dictator".

• Sarkozy said they needed to strengthen sanctions against the Syrian government and assist the opposition in coming together and uniting for joint action. The main obstacle to progress was not Russian and Chinese opposition in the UN but the need for the Syrian people to unite, he said. The revolution cannot come from outside, he said.

David Cameron and Nicolas Sarkozy at a press conference in Paris today. Photograph: Benoit Tessier/Reuters

• Cameron also seemed to sidestep convention by coming close to endorsing Sarkozy in his battle to be re-elected as French president this year. Cameron told Sarkozy he would be following his fortunes on the campaign trial and "I wish you well". Asked if he would join Sarkozy on the stump, as Angela Merkel has done, the British PM said he was not sure that that would have a positive effect. The two leaders seemed to have a warm rapport and their conflicts over the eurozone crisis seemed to have been set to one side, with Sarkozy even saying that he might have acted as Cameron had done if he were British prime minister.

12.34pm: Friends of the Earth has also come out against the UK-French nuclear deal and calling for investment in renewables instead. Paul Steedman of the lobby group said:

Cameron's deal today will leave British taxpayers footing a massive bill for new nuclear plants we don't need and can't afford - while EDF continues to rake in huge profits.

Billions of pounds have already been spent subsidising nuclear – and dealing with nuclear waste is expected to cost many billions more. We're already seeing lengthy delays and spiralling costs at the two nuclear reactors currently under construction in Europe.

Meanwhile solar panels and wind turbines are becoming more affordable - and they are clean and tested alternatives we know could provide tens of thousands of new jobs with the right government support.

12.33pm: The BBC is reporting that the government is going to supply food rations for 20,000 people in Syria and will employ an adviser to liaise with agencies.

12.31pm: My colleague Adam Vaughan adds that the only thing he can see in the French-British nuclear deal is the £15m investment in a new world class training campus in Bridgwater, Somerset for EDF employees, new starters and the local community.

12.30pm:John Vidal, the Guardian's environment editor, writes that environmental activists who have occupied the site of what is planned to be Britain's first new nuclear power station in over 20 years are accusing French energy giant EDF of "ignoring democracy" and starting work on the £10bn project without permission to build the station. John writes:

Eight people have occupied the semi-derelict Langborough farmhouse on land due to be cleared within weeks to make way for the twin-reactor Hinkley Point C power station in Somerset. The £100m preparatory earth works, which were formalised today in Paris with Cameron and Sarkozy signing an agreement, will remove a volume of soil and rock four times the volume of Wembley stadium from the 500 hectare site, destroy a site of special scientific interest and several historic buildings.

EDF today admitted they did not have permission to start building the power station but said the infrastructure planning commission (IPC) had accepted their application for a development consent order (DCO), which would allow them to build it. In addition, a spokesman said the company had received permission from West somerset district council to begin "preparatory works".

But the protesters said the preparatory works were so large they constituted the effective start of the power plant construction and rendered the consultation period, when arguments for and against the power station could be heard, meaningless.

"The government has steamrollered this through. Either EDF is behaving in a grossly insensitive way by clearing 500 hectares of land, or they know that they will get permission to build the nuclear station. If it is a done deal then the consultation is bogus. The democratic process has been dispensed with completely," said Theo Simon, one of the eight protesters now in the farmhouse.

The IPC's examination and decision making is likely to take nearly a year, by which time the site will have been cleared of all vegetation.

"This is like someone who has not got planning permission digging the foundations of a new house. The extent of the activity, the clearance of most vegetation, hedges and trees, the excavation of more than four million cubic metres of soil and rocks, the re-routing of underground streams, the creation of roads and roundabouts, major changes to the landscape ... mean it is effectively the beginning of construction of the proposed Hinkley C nuclear power station," said Stop Hinckley C spokesman Crispin Aubery, who claimed that the council had been leaned on heavily to allow preparatory work to begin.

12.06pm: France and Britain together make up half of Nato's defence spending, Cameron says. We both want to increase and modernise our capabilities, he says.

Sarkozy says other countries are welcome to help if they will move at the same pace as Britain and France.

With that, the two leaders shake hands, clasp each other's arms and pat each other's backs in the manner of top politicians, and leave the podium.

12.03pm: Sarkozy says he respects the way Britain has remained respectful towards its traditions while embracing modernity.

Cameron says it is appalling and the government is "butchering and murdering its own people".

We have to recognise that there are different circumstances in Syria than in Libya: in Libya we had a UN resolution, Arab League calls for action, an opposition representing the whole country, he says.

We have to put all the pressure we can on Bashar al-Assad to make him stand down, Cameron says.

I want us to go on working and thinking and asking ourselves what more we can do, Cameron says, to get rid of this "brutal dictator".

It is difficult and complicated, the PM says.

11.57am: Sarkozy ends his answer saying he is delighted to benefit from the support of Cameron.

11.51am: We'll be following your fortunes on the campaign trail in the next few weeks, Cameron tells Sarkozy, "and as I said I wish you well".

Leaders are usually studiously neutral in others' election campaigns - for the very good reason that the leader they back may not win - but that strayed close to Cameron coming out in support of Sarkozy.

Cameron is asked if he will join Sarkozy on the campaign trail as Angela Merkel has done.

I admire Sarkozy's leadership and courage, says Cameron. The future is an issue for the French people, Cameron says. But he is not sure that if he joined the campaign trail for Sarkozy it would have a positive effect, the PM says.

Sarkozy says he always likes it when people say nice things about him. But he does not answer the question of whether he would like to have Cameron campaigning for him.

Turning to Cameron's veto of a European treaty on the eurozone, Sarkozy says perhaps if he was in Cameron's position he would have defended British interests in the same way Cameron did.

11.49am: The defence co-operation they have discussed today is real and substantial, Cameron says.

We do sometimes disagree on European issues, the PM says. We need to understand that. But our economic collaboration is extremely strong, he says.

We both want to see a stable and successful eurozone, Cameron says.

11.48am: Cameron pays tribute to Sarkozy's role in Libya and points out that it is the first anniversary of the uprising there. Leadership from Sarkozy made a decisive difference for the Libyan people, the PM says.

It is an honour to work with Sarkozy.

There has not been closer French-UK co-operation since the second world war, he says.

11.47am: Cameron thanks "Nicolas" too, saying he has visited "this great capital city" more than any other since becoming prime minister.

Sarkozy: Except Brussels.

Cameron: But as we've discussed that is not the same thing. That's won me some votes in Belgium ...

11.32am: Sarkozy and Cameron's talks have overrun, and their joint press conference is now expected at 12.15pm.

11.14am: Gerry Wolff of campaign group Energy Fair has just been speaking on BBC News. He said:

Nuclear power does not meet the objectives the government itself has set in terms of energy policy. If you look at the situation around the world, solar power is growing at about 30% a year, wind power's growing at about 30% a year, meanwhile nuclear power is basically marking time or shrinking. It's just not a good option from a commercial point of view.

He said he was currently drafting a report on the commercial risks of nuclear power.

For anyone considering putting money into nuclear power it's a very, very risky thing. Amongst the risks is … the high level of subsidies which is enjoyed by nuclear power. We have actually submitted a formal complaint to the European commission about subsidies for nuclear power and at any time either by action of the European commission or by legal action or by action of politicians those subsidies may be withdrawn, and the investors cannot rely on the subsidies being there.

10.52am: My colleague Adam Vaughan, the editor of environmentguardian.co.uk, says it is not clear what is new in the Franco-British partnership announced today. It appears to be mainly a reaffirming of existing plans for French state-owned EDF to build a new fleet of reactors in the UK later this decade, Adam writes.

The Keir/BAM Nuttall deal for work at Hinkley in Somerset was confirmed last year and Areva already had a supply chain deal with Rolls-Royce, for example.

But the plans are big business for the French government - it owns around 85% of EDF and Areva, the nuclear plant builder. For the UK, the new fleet - the biggest planned in Europe - offers a chance to create jobs and generate low carbon electricity that will help the coalition hit its carbon targets. It has brought in a carbon floor price specifically to help aid new nuclear.

To avoid planning battles, the proposed eight new reactors for the UK are all on or adjacent to existing nuclear sites. But that hasn't stopped anti-nuclear activists in Somerset squatting at a farmhouse on the site of the new Hinkley C reactor. Hinkley looks set to be the battleground for new nuclear in the UK, as it's first in line and has seen the biggest protests, with hundreds of people blockading the site last year.

We'll have more on that from the Guardian's environment editor, John Vidal, shortly.

10.47am: Not everyone is delighted with the nuclear deal. Greenpeace says "the economics of new nuclear reactors don't stack up". The lobby group's Doug Parr sends this statement:

No amount of talking up of the French nuclear industry by David Cameron and Nicolas Sarkozy will cover up the fact that the economics of new nuclear reactors don't stack up. The track record of EDF in building new nuclear power stations on time and to budget is appalling. Recently the independent risk agency Standard and Poor downgraded EDF's creditworthiness. All this came just a few months after a French judge sentenced a number of EDF senior executives to prison for unscrupulous acts of spying. French nuclear power is no longer popular even in France.

So instead of using UK taxpayers' money to prop up failing French industries, David Cameron should follow the lead of Germany and concentrate on securing vast numbers of jobs and economic growth in the rapidly expanding clean energy industries such as wind and solar power.

10.34am: Labour has sent a fairly anodyne quote about the French nuclear deal. Caroline Flint, the shadow energy secretary, said:

Nuclear power has a vital role to play as part of a more sustainable, balanced and low-carbon future energy mix, to make us less reliant on volatile fossil fuel prices, increase our energy security, and keep prices down for families.

The UK must learn the lessons from the development of new nuclear power stations in France so we can deliver new nuclear projects in this country on time and on budget.

10.29am: Before the summit, Cameron also spoke about working with France regarding the Middle East. Today is the first anniversary of the start of the uprising against Gaddafi in Libya. Cameron said:

One year on from the Libya uprising, we are working together to stand up to the murderous Syrian regime and to stop a nuclear weapon in the hands of Iran. At the United Nations, we co-sponsor more than three quarters of security council resolutions. Our commercial relationship is deep and growing, with exports increasing and French investment sustaining almost 10,000 jobs in the UK. Our militaries are working together on cutting-edge military technology. This relationship is vital for the national security and the prosperity of both Britain and France.

Patrick writes that deals to build unmanned drones will also be on the agenda today. He writes:

The two countries dominate European defence spending and will mark the next stage in defence co-operation by agreeing in principle to build unmanned drones by 2020. The Europeans, taking the dominant forward role in the Libyan air campaign, were struck by their lack of unmanned aerial surveillance capability, leading to a heavy reliance on US drones. Britain and France will sign a preliminary statement of intent and joint research to be led by Dassault and BAE.

On Syria, the two want to provide "practical advice" to the rebel Free Syrian Army, which is made up of defected soldiers, but are not planning to provide arms or any direct support on the ground, Patrick writes.

The work of special forces or the provision of communications equipment is not discussed by either government. Downing Street officials have met with Syrian leaders in exile and were less impressed by their unity and quality than they were in the case of their counterparts in Libya. The opportunity for practical diplomatic help through the UN is heavily restricted due to the opposition of the Russians and Chinese, so the focus has been on building a Syrian contact group built round Arab nations.

Cameron is determined that Bashar al-Assad's regime is not replaced by something worse, and wants to ratchet up the pressure on the regime by raising the prospect of war crimes charges at the Hague.

Disputes over the eurozone's problems between the two men will be downplayed.

10.19am: Cameron spoke about the nuclear co-operation plans before the summit. He said:

At our last summit, we signed a historic partnership on defence. Today, we will match that ambition on nuclear energy. As two great civil nuclear nations, we will combine our expertise to strengthen industrial partnership, improve nuclear safety and create jobs at home.

The deals signed today will create more than 1,500 jobs in the UK but they are just the beginning. My goal is clear. I want the vast majority of the content of our new nuclear plants to be constructed, manufactured and engineered by British companies. And we will choose the partners and technologies to maximise the economic benefits to the UK. Today marks an important first step towards that. A good deal for Britain and a good deal for France.

Ed Davey, the energy secretary, said:

We need hundreds of billions of pounds of investment in clean energy projects in the UK. This will bring high-skilled job opportunities the length and breadth of the country. Construction workers, engineers, technicians - they will all have a role to play. There are plans for new nuclear in Somerset, Suffolk, Cumbria, North Wales and Gloucestershire. Supply chains will spring up too, and extend the reach of economic benefit across the country … The deals we will see signed today reflect our ongoing desire to work closely together with our French allies and the private sector on nuclear, and across the energy mix.

10.12am: The prime minister's car has just arrived at the Elysee Palace. David Cameron stepped out of his car and was greeted by Nicolas Sarkozy on the steps. The two men shook hands in a businesslike fashion, and disappeared inside the building.

10.11am: The Press Association has more details on the nuclear deal between Britain and France:

Downing Street said that by joining forces in the nuclear sector, Britain and France can develop a competitive supply chain capable of seizing opportunities around the world.

Rolls-Royce will today sign a £400m deal with French energy giant Areva to supply services to the first EPR [nuclear] reactor at Hinkley Point in Somerset, with a commitment for future EPR sites in the UK. Rolls-Royce will build a dedicated factory in Rotherham and the deal will underpin more than 1,200 jobs in the company and its supply chain.

Meanwhile, France's EDF will conclude a £100m agreement with Keir/BAM Nuttall for preliminary works at Hinkley Point - the first major construction project to be awarded in the £10bn project. EDF will invest in a £15m training campus in nearby Bridgwater.

10.02am: A Citroen pulls up outside the Elysee Palace. The BBC identifies the man in the dark winter coat who steps out of the car first as David Cameron and then as Nicolas Sarkozy. But it isn't either of them.

10.01am: Cameron is about to arrive at the Elysee Palace. BBC News and Sky News both have their cameras trained on the steps of the palace.

9.48am: Hello, and welcome to today's Politics blog, with Paul Owen standing in for Andrew Sparrow.

David Cameron is travelling to Paris today to seal an agreement with France to co-operate on civil nuclear energy, which will pave the way for the construction of a new generation of nuclear power plants in Britain.

According to the Press Association, deals worth more than £500m between British and French companies will allow work to start on new facilities, creating more than 1,500 jobs across the country.

Cameron said that this just the beginning and that the investment could eventually be worth £60bn and create 30,000 jobs.

Cameron and Sarkozy are to sign a joint declaration on the nuclear co-operation at the UK-France summit in Paris today.

Also on the agenda for talks between the two men will be the unrest in Syria and concerns over Iran's possible attempts to build nuclear weapons.

Sarkozy formally announced his candidacy for re-election as French president earlier this week, although he is trailing Socialist challenger Francois Hollande in the polls. The election will be held on 22 April and 6 May.